-Let's think about the encodings of booleans, numerals and lists in System F, and get datastructures with the same explicit form working in OCaml. (The point... so we won't rely on OCaml's native booleans, integers, or lists.)

+Let's think about the encodings of booleans, numerals and lists in System F,

+and get data-structures with the same form working in OCaml. (Of course, OCaml

+has *native* versions of these datas-structures: its `true`, `1`, and `[1;2;3]`.